Berlin 2005 – scientific programme

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SYOO: Organic Optoelectronics and Photonics

SYOO 6: Poster

SYOO 6.43: Poster

Monday, March 7, 2005, 18:00–20:00, Poster TU A

Spatially inhomogeneous distribution of traps in organic diodes — •Arne Fleissner, Wieland Weise, and Heinz von Seggern — Electronic Materials Department, Institute of Materials Science, Darmstadt University of Technology, Petersenstr. 23, D-64287 Darmstadt, Germany

The performance of organic light emitting devices is strongly influenced by charge carrier traps. It is therefore of great importance to combine theoretical models and experimental results in order to develop a better understanding of the effects of traps on the device characteristics. In this talk, the influence of the spatial distribution of shallow traps on space charge limited current (SCLC) through organic diodes is investigated. Devices with a well-defined spatial distribution of traps are prepared by means of co-deposition of the small molecule organic semiconductors 1-NaphDATA as the host and α-NPD as the dopant. The resulting 1-NaphDATA films consist of three layers, wherein one is homogeneously doped with α-NPD, which creates well-known shallow traps for holes. The position of the doped layer has a strong influence on the SCLC characteristics of the diodes. A model for unipolar SCLC through layers with a disparate concentration of shallow traps is presented. The model describes the experimental results quantitatively. It is employed to calculate the spatial distributions of the charge carrier density and the electric field strength in the differently doped devices.